Pincers for stripping the ends of electric conductors covered with insulating material



Dec. 25, 1962 HER 3,069,943

- E. F lSC PINCERS FOR STRIPPING THE ENDS OF ELECTRIC CONDUCTORS COVERED WITH INSULATING MATERIAL Filed July 14, 1961 3| ELEMER FISCHER INVEN T7Qm BY Fig.1

United States Patent Ofiice 3,069,943 Patented Dec. 25, 1962 3,069,943 PINCERS FOR STRIPPING THE ENDS F ELEC- TRTC CONDUCTORS OVERED WITH INSULAT- HWG MATERIAL Elemer Fischer, 25 Rue Falguiere, Paris, France Filed July 14, 1961, Ser. No. 124,200 3 Claims. (Cl. 81-95) The present invention has for its object an improvement in pincers for stripping insulating material from the ends of insulated electric conductors.

It is a purpose of the invention to provide an apparatus which is less tiring for the operator to handle than wire strippers of known types and the operation of which is more rapid, thereby permitting as a result high rates of production and performance.

The apparatus in accordance with the present invention is characterized by the fact that it comprises, in combination with pincer-jaws of a conventional type, a compressed-air jack with a device for actuating said jack, and a kinematic device for transmitting the energy of the jack to the pincer-jaws.

The invention will be more clearly understood by means of the description which follows below with reference to a form of embodiment which is given by way of example and not by way of limitation, reference being made to the accompanying drawings, in which:

FIG. 1 is a perspective view of the mechanism of the apparatus in accordance with the present invention, and

FIG. 2 is a perspective view of the entire apparatus in condition of service.

The pincers for stripping the ends of insulated electric conductors principally comprise two arms 15 and 16 with openings 15a and 16a for receiving the electric wire. These arms are articulated on a fulcrum pin 10. The arm 15 is fitted with cutting means including two knives 17 and 18, the profiles of which comprise circular cut-out portions 17:: and 18a which, when the knives are brought into contact with each other, form a circle having a diameter which is slightly larger than that of the metallic conductor to be stripped. The knives can easily be taken apart and replaced, and are chosen from a set according to the diameter of the wire to be stripped. The arm 16 is provided with clamping means including two jaws 19 and 20. The jaw 19 is mounted on the arm 16 and forms an anvil, while the jaw 20 is adapted to slide along the arm 16 and forms a movable clamping member; the jaw 20 is integral with a guide strip 21 on the extremity of which is pivotally mounted a link-rod 22. The manner in which the knives 17 and 18 are fitted in the arms 15 is similar to that in which the jaws '19 and 20 are fitted in the arms 16. The knife 18 is a rigidly fixed blade on the arm 15, whereas the knife 17 is a movable blade member capable of sliding along the arm 15. The knife 17 is also integral with a guide strip which is not shown in the drawings, but the extremity of which is pivotally coupled to a link-rod 23. The arms '15 and 16 are drawn towards each other by means of a spring 24. The jaw 20 together with the guide strip 21 is held applied against and in sliding contact with the arm 16 by means of an auxiliary guiding member which has not been illustrated for the sake of simplicity of the drawings. The knife 17 is similarly held against the arm 15.

In accordance with the invention, a jack 30 acts on the link-rods 22 and 23 for the purpose of drawing together and separating the arms by means of the device which forms the subject of the present invention. The jack 3tl is provided at one extremity thereof with an admission pipe 30a; in the interior of the jack, a piston 30 is urged by a spring 30" towards the admission end. The piston is fixed to a rod 3-1 which is pivotally coupled to the center of a drawbar or tie-rod 32 at the extremities of which are pivotally coupled link-rods 33 and 34. The other extremities of the link-rods drive the extremities 35a and 36a of two levers 35 and 36 which are articulated on the fulcrum pin 10 and form a scissor linkage, the extremities of said levers being pivotally coupled to the extremities 22a and 23a of the link-rods 22 and 23. That extremity of the jack which is located opposite to the extremity at which compressed air is admitted is mounted on a member 38 in the shape of a horseshoe, the top portion of which has been broken away for the sake of the simplicity of the drawings. The fulcrum pin 10, about which are articulated the two arms 15 and 16 and the two levers 35 and 36, is fixed at the two extremities thereof to the member 38.

The device operates as follows: when at rest, the two arms 15 and 16 are held against each other by the spring 24, while the spring 30" located inside the jack or pneumatic cylinder thrusts the piston towards the right hand side of the figure and applies tractive force on the rod 31 which, through the intermediary of the tie-rod 32, the linkrods 33 and 34 and the levers 35 and 36, produces a pressure on the link-rods 22 and 23, the effect of this pressure being to hold the jaws 19 and 20 and the knives 17 and 18 at a distance away from each other, and also to hold the two arms 15 and 16 against each other over and above the action of the spring 24. The conductor to be stripped is placed in the openings 15a and 16a of the arms, the end of the conductor being placed on the same side as the knives and projecting from these latter by the length to be stripped. When compressed. air is admitted into the jack, the rod 31 is forced towards the left of the figure and, through the intermediary of the tie-rod 32 to which are coupled the link-rods 33 and 34, applies movements of thrust against the extremities 35a and 36a of the levers 35 and 36. These levers convert these movements of thrust into tractive force applied on the extremities 22a and 23a of the link-rods 22 and 23. Since the two arms 15 and 16 remain applied against each other under the action of the spring 24, the beginning of any movement of the link-rods will have the effect of drawing the jaw 21) towards the jaw 19 as a result of traction on the guide strip 21, the knife 17 being similarly drawn towards the knife 18, until the jaw 20 clamps the wire against the jaw 19, while the knives 17 and 18 cut into the insulating material after having been brought close together. The jaw 20 cannot be displaced any further; it follows as a result that the movements of traction of the link-rods 22 and 23 then separate the arms 15 and 16. On one side, the electric wire together with its insulation will remain gripped between the jaws 19 and 20, while the knives 17 and 18 will tear off the insulating material which covers the free end of the wire. An accessory device which is known per se, and which has not been illustrated in the drawing, is provided for the purpose of withdrawing the knives and the jaws when the arms 15 and 16 have opened out to a sufficient distance, in such a manner as to make it possible to remove the stripped wire without causing damage to this latter. When the pressure inside the jack is no longer applied, the complete device is restored to its initial condition under the action of the spring 24 and of the internal spring 30 of the cylinder 30.

FIG. 2 illustrates an apparatus for the practical application of the improved pincers in accordance with the invention. The pincers are enclosed in a casing 40. This casing is provided at one extremity thereof with an opening 41 for the passage of the arms 15 and 16. On the top face of the casing is mounted a ring 42 which permits the apparatus to be suspended by means of a spring 43. Beneath the casing is provided an operating 3 hand-grip 45, on the front face of which is mounted the push-button 46 of the distributor which supplies compressed air to the jack. A flexible conduit 47 connects the apparatus to a suitable source of compressed air.

Since the weight of the apparatus is in fact balanced by the spring, the operator need not supply any effort to carry the apparatus; neither is there required any effort on his part to operate the said apparatus, since the energy is provided by means of compressed air. This apparatus is therefore capable of high working speed and high performance without thereby inflicting any physical strain on the personnel, which is the cause of poor productivity or interruption of work.

What I claim is:

1. An apparatus for stripping an insulating covering from an electrical conductor, comprising an elongated support; a pneumatic cylinder rigid with said support and having a piston reciprocable therein; a pair of arms secured to said support at one extremity thereof, at least one of said arms being swingable about an axis perpendicular to said support toward and away from the other arm; clamping means on one of said arms for engaging said covering and said conductor, said clamping means including an anvil fixed to the respective arm and a movable clamping member slidably displaceable on said respective arm toward and away from said anvil; cutting means on the other of said arms, said cutting means including a fixed blade and a movable blade member slidably displaceable toward and away from said fixed blade; a pair of links each pivotally connected with a respective one of said members; a pair of levers fulcrumed on said support and forming a scissor linkage; each of said levers being articulated to a respective one of said links at a corresponding extremity; spring means interconnecting said arms for biasing same toward each other; a drawbar secured to said piston and reciprocable thereby extending generally transversely to the direction of reciprocation of said piston; and a pair of connection rods each pivotally connected to a respective extremity of said drawbar and to a respective one of said levers at an extremity thereof remote from said corresponding extremity; and a restoring spring in said cylinder urging said piston away from said arms, thereby disengaging said clamping and cutting means, said piston being shiftable under pneumatic pressure against the force of said restoring spring for successively engaging said clamping and cutting means and spreading said arms.

2. An apparatus according to claim 1 wherein said support comprises a plate having a transverse flange at an extremity thereof remote from said arms, said cylinder being secured to said flange and said piston having a rod extending through said flange while being reciprocable generally parallel thereto.

3. An apparatus according to claim 1 comprising a housing enclosing said cylinder, said support, said levers and said links, further comprising pneumatic control means for operating said cylinder secured to said housing along a lower surface thereof; and resilient supporting means secured to an upper surface of said housing for taking up the weight of said apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 2,523,936 Axelsen Sept. 26, 1950 2,996,939 Meier Aug. 22, 196.1

FOREIGN PATENTS 1,105,549 France July 6, 1955 1,147,235 France June 3, 1957 

